/*

 * Licensed to the Apache Software Foundation (ASF) under one

 * or more contributor license agreements.  See the NOTICE file

 * distributed with this work for additional information

 * regarding copyright ownership.  The ASF licenses this file

 * to you under the Apache License, Version 2.0 (the

 * "License"); you may not use this file except in compliance

 * with the License.  You may obtain a copy of the License at

 *

 *     http://www.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License.

 */

package com.bff.gaia.unified.runners.core.construction;



import com.bff.gaia.unified.sdk.runners.AppliedPTransform;

import com.bff.gaia.unified.sdk.transforms.PTransform;

import com.bff.gaia.unified.sdk.values.PCollection;

import com.bff.gaia.unified.sdk.values.PValue;

import com.bff.gaia.unified.sdk.values.TupleTag;

import com.bff.gaia.unified.vendor.guava.com.google.common.collect.Iterables;



import java.util.Map;

import java.util.Set;



import static com.bff.gaia.unified.vendor.guava.com.google.common.base.Preconditions.checkArgument;



/** */

public class PTransformReplacements {

  /**

   * Gets the singleton input of an {@link AppliedPTransform}, ignoring any additional inputs

   * returned by {@link PTransform#getAdditionalInputs()}.

   */

  public static <T> PCollection<T> getSingletonMainInput(

      AppliedPTransform<? extends PCollection<? extends T>, ?, ?> application) {

    return getSingletonMainInput(

        application.getInputs(), application.getTransform().getAdditionalInputs().keySet());

  }



  private static <T> PCollection<T> getSingletonMainInput(

      Map<TupleTag<?>, PValue> inputs, Set<TupleTag<?>> ignoredTags) {

    PCollection<T> mainInput = null;

    for (Map.Entry<TupleTag<?>, PValue> input : inputs.entrySet()) {

      if (!ignoredTags.contains(input.getKey())) {

        checkArgument(

            mainInput == null,

            "Got multiple inputs that are not additional inputs for a "

                + "singleton main input: %s and %s",

            mainInput,

            input.getValue());

        checkArgument(

            input.getValue() instanceof PCollection,

            "Unexpected input type %s",

            input.getValue().getClass());

        mainInput = (PCollection<T>) input.getValue();

      }

    }

    checkArgument(

        mainInput != null,

        "No main input found in inputs: Inputs %s, Side Input tags %s",

        inputs,

        ignoredTags);

    return mainInput;

  }



  public static <T> PCollection<T> getSingletonMainOutput(

      AppliedPTransform<?, PCollection<T>, ? extends PTransform<?, PCollection<T>>> transform) {

    return (PCollection<T>) Iterables.getOnlyElement(transform.getOutputs().values());

  }

}